Debbie Reynolds Bares Massive Facial Bruise On HBO Documentary "Bright Lights"

Debbie Reynolds bared a massive bruise on her face during HBO's posthumous documentary starring Carrie Fisher ... after falling flat on her face at home.

In the film "Bright Lights" that aired this weekend, Debbie is seen sporting what looks to be a painful bruise around her mouth, after it's revealed she became dizzy and fell at home.

She got injured in the process of getting an auction together to sell some of her Hollywood memorabilia ... to neutralize debt she'd incurred.

Her son, Todd Fisher, says the fall didn't stop her from going on about her business.